Thermal time delay relay



Nov. 17, 1959 F. A. ORECHIO THERMAL TIME DELAY RELAY Filed June 12. 1958 INVENTOR Ram/(A- Oreclzzio BY ATTORNEY va--- .ii

United States Patent THERMAL TllVIE DELAY RELAY Frank A. Orechio, Nutley, NJ.

Application June 12, 1958, Serial No. 741,560

3 Claims. (Cl. 200-122) The present invention relates to thermal relays.

A primary object of the invention is to provide a thermal relay of the time delay type, constructed in a novel and simplified manner, so as to insulate the relay contacts, heating elements and associated parts from mechanical vibrations transmitted through the relay base.

A further important object of the invention is to provide a thermal relay in which the operating parts to be insulated from vibration are all bodily mounted upon a rigid unitary support separate from the relay base.

Another object is to provide in a thermal time delay relay novel heating element means for the movable relay contact.

A further object of the invention is to provide a relay of the above-mentioned character in which the independent supporting means for the relay parts is bodily mounted upon the lead wires associated with the prongs of the relay base.

Still another object of the invention is to provide a relay of the above-mentioned character which is highly economical in construction, reliable and efiicient in operation, rugged and durable, and long-lasting in use.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a plan view of a thermal relay in accordance with the invention, partly in section.

Figure 2 is a side elevation of the relay with the cover or envelope removed.

Figure 3 is a central vertical section taken on line 33 of Figure 2.

Figure 4 is an exploded perspective view of the relay with parts omitted.

Figure 5 is a schematic view or diagram showing the electrical circuits for one preferred type of relay according to the invention.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral designates a standard or conventional octal relay base, including a disc-like body portion 11 formed of molded Bakelite, or. the like, which base carries the usual eight depending circumferentially spaced metal prongs 12, rigidly anchored therein in a conventional manner. While the relay base 10 has been shown as a standard octal base, it should be understood that other bases may be employed with different numbers of the metal prongs 12, and I do not wish to limit the invention to a single base having a particular number of prongs.

In the embodiment shown, four relatively stiff lead wires 13, 14, and 16 are soldered or otherwise conventionally fixed within the tops. of the metal prongs 12 and extend above the tops of the metal prongs and are bent" inwardly adjacent to the top of the base 10, as

7, 2,913,554 Patented Nov. 17, 1959 shown. The particular prongs 12 shown connected with the lead wires 13, 14, 15 and 16 are selected to adapt the relay to desired circuitry in which it is used, and it is to be understood that within the scope of the invention the lead Wires may be electrically connected with various ones of the prongs 12, in accordance with various uses of the relay in different circuits. The upper extensions 19 of the several lead wires 13-16 are vertically disposed as best shown in Figure 3, and substantially concentrically arranged with respect to the central axis of the base 10.

An independent glass or plastic supporting element or platform 17 is arranged above the relay base 10 and spaced somewhat therefrom and concentric therewith. The glass platform 17 is provided upon its lower side with a plurality of circumferentially spaced depending integral projections 18, and the top vertical extensions 19 of the lead wires 13-16 extend through and are embedded and fused Within selected ones of the projections .18, as shown.

A plurality of upstanding vertical rigid metal pins 20, corresponding in number and spacing to the projections 18, are also embedded and fused within the top of the glass platform 17, and these pins 20 are electrically connected with the top extensions 19 of the lead wires within the interior of the glass platform, as shown. The pins 20 extend vertically above the top of the platform 17 for a substantial distance. The entire platform 17 and associated elements is thus bodily supported upon the several relatively stiff lead wires 13-16, and the glass platform is thus fioatingly mounted in spaced rela tion to the relay base 10 and substantially concentric therewith.

One side-by-side pair of the vertical pins 20 has welded thereto at the inner sides thereof a transverse metal plate 21, carrying an upstanding elongated metallic stationary relay contact arm 22, the lower end of which arm is welded to the plate 21, as shown. The stationary contact arm 22 extends vertically for a substantial distance above the tops of the rigid pins 20, and has fixedly secured to its upper end by welding or the like the stationary contact 23 of the relay.

A further metal plate 24 is welded to the opposite sides of the pair of pins 20 carrying plate 21, and the plate 24 has an upstanding extension 25 integral therewith spaced from and opposite the contact arm 22. The plate extension 25 has a screw-threaded opening 26 formed therethrough, receiving an adjusting screw 27 for the contact arm 22, the inner end of the screw 27 being adapted to engage the outer side of arm 22, as shown.

A further pair of the pins 20 which are substantially diametrically opposed upon the glass platform 17 and spaced from the pins 20 carrying the arm 22 have an elongated plate 28 welded thereto at the same elevation as the plate 21. An upstanding movable bi-metallic contact arm 29 formed of metals having different thermal coefficients of expansion and contraction is arranged in opposed spaced relation to the arm 22 and has its lower end welded to the inner face of the plate 28. The movable contact 30 of the relay is welded to the upper end of the arm 29 in spaced opposed relation to the stationary contact 23.

A relatively small flattened sleeve 31 of mica or like electrical insulating material is frictionally mounted upon the bi-metallic contact arm 29, as shown, and this mica sleeve carries a winding of very fine wire such as Nichrome wire, adapted to serve as a heating element for the bimetallic arm 29. The heating element winding 32. is wound upon the exterior of the sleeve 31 and is therefore insulated from the bi-metallic arm 29. One end of the heating element winding 32 is electrically connected at 33 to the upstanding pin 23, which in turn is electrically connected with the lead wire 15. The other end of the winding 32 is electrically connected at with one of the pins 20 which terminates within the glass platform 17 and has no lead wire connected with one of the prongs 12.

An upstanding metallic arm 35 is fixedly secured by welding to the outer side of the pin 20 which is electrically connected with the lead wire 16, and arranged near the side of the platform 17 remote from the stationary contact arm 22 and associated elements. A flattened mica sleeve 36 considerably larger than the sleeve 31 is frictionally mounted upon the upstanding arm 35, and a second heating element winding 37 of fine wire is wound exteriorly upon the mica sleeve 36 and electrically insulated thereby from the arm 35. One end of the winding 37 is electrically connected at 38 to the metallic arm 35, and its opposite end is electrically connected at 39 to the same pin 20 with which one end of the winding 32 is connected at 34. The two heating element coils or windings 32 and 37 are thus electrically connected in series through one of the pins 24) which does not have a lead wire leading to a prong 12 of the relay.

A cylindrical envelope or cover 49 for the relay is provided, preferably formed of sheet metal, and the lower open end of this envelope engages snugly over the raised cylindrical portion 41 of the base lltl. The base 16 is provided at circumferentially equidistantly spaced points with a plurality of peripheral recesses 42, and correspondingly spaced lower marginal portions 4 3 of the sheet metal envelope 4d are crimped within the recesses 42 for fixedly securing the envelope 40 to the base it). If preferred, the envelope 40 may be formed of glass or a suitable plastic material, and secured to the base It) with a suitable plastic glue. In the latter case, a hermetic seal may be formed between the base and the envelope or cover 40.

In order to stabilize the glass platform 17 and to insulate the same against lateral vibrations, and to maintain the platform 17 centered with respect to the axis of the base 10, there may be provided between the periphery of the platform 17 and the side wall of the cylindrical envelope 40 a wavy resilient plastic spacer spring 44, shaped as shown in Figure l, and contacting the periphery of the platform 17 and the side wall of the envelope 40 at a plurality of circumferentially equidistantly spaced points. I The plastic spacer 44 may merely frictionally engage the platform 17 and the envelope 4t and need not be permanently attached to either element. If preferred, the stabilizing spacer .4 may be omitted entirely from the assembly.

With reference to diagrammatic Figure 5, it may be seen that one circuit is formed through the prong 12 having the lead wire 14 and through the upstanding pin 20 which is electrically connected with the lead wire 14. This circuit continues through the stationary contact arm 22 and the stationary contact 23. When the relay contacts 23 and 30 are closed, the circuit continues through the movable contact 30 and the movable bi-metallic arm 29 and the plate 28, and then through the upstanding pin 20 which is electrically connected with the lead wire 13 leading to another of the relay prongs 12.

A second electrical circuit exists in the relay through the prong 12 having the lead wire 16, and through this lead wire to the upstanding pin 20 which carries the metallic arm 35. The circuit continues through the heating element winding 37, connected with the arm 35, and then through the heating element Winding 32 which is electrically connected in series with the winding 37 as previously described. The second circuit continues from the winding 32 to the pin 20 which is connected at 33 with the winding 32, and then through this pin 2G to the lead wire 15, electrically connected with another of the prongs 12 of the relay.

In the embodiment shown, the relay contacts 23 and 30 are normally open, and the above-described circuit through these relay contacts may be energized at all times while the relay is in use. The other described circuit through the heating element windings 37 and 32 is periodically energized in accordance with the control function which the relay is serving in a particular application or circuit. When the circuit through the windings 37 and 32 is energized, these windings will impart heat to the bi-metallic arm 29, and this arm will move toward the relatively stationary arm 22 until the circuit through the relay contacts 23 and 34) is closed. The time delay factor of the relay is controlled or adjusted by the particular setting of the adjusting screw 27. When the circuit through the heating element windings 37 and 32 is again opened, no further heat will be transmitted to the bi-metallic arm 29 of the relay, and the movable relay contact 30 will separate from the stationary contact 23 and the circuit through the two relay contacts will again be open.

During the operation of the relay as above-described, the heating element winding 37 supplements the action of the heating element winding 32 which is mounted directly upon the bi-metallic arm 29. The Winding 37 is made somewhat larger than the Winding 32, due to the fact that the winding 37 is spaced somewhat from the bi-metallic arm, and in order to be effective for actuating the arm 29, a greater amount of heat must be produced by the winding 37 than by the winding 32. Both of the windlugs 32 and 37 operate simultaneously and in conjunction with each other to cause the necessary movement of the bi-metallic arm 29 for closing the relay contacts 23 and 30.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Having thus described my invention, I claim:

1. A thermal time delay relay comprising a mounting base, metallic prongs secured to said mounting base, substantially stiff lead wires connected with said prongs and extending above said base, a glass platform separate from said base fused to said lead wires and supported thereby, metallic pins fused to said glass platform and projecting above the same, movable and stationary relay contact means electrically connected with and carried by said pins, adjustment means for said stationary relay contact means mounted upon said pins, heater means for the movable relay contact means electrically connected with and mounted upon said pins, an envelope enclosing said relay contact and heater means and said platform and secured to said base, and a spacer element disposed between the side wall of said envelope and said platform for stabilizing the platform and centering it with respect to said base.

2. A thermal relay comprising an insulating mounting base, a plurality of metal prongs secured to said base and projecting beyond one side thereof, a plurality of lead Wires electrically connected with said prongs and extending above said base, a glass platform separate from said base, and substantially smaller than the base arranged above the base and attached to said lead wires and bodily supported thereby centrally of the base, a plurality of substantially rigid metal pins attached to said glass platform and projecting thereabove and electrically connected with said lead wires, a metallic plate secured to one pair of said pins including one pin electrically connected with one of said lead wires and one pin without a lead wire, a relatively stationary contact arm secured to said plate, a stationary relay contact secured to said arm, an adjusting screw associated with said arm to adjust the position of the same, a second plate attached to another pair of said pins including one pin electrically connected with another of said lead wires and a pin without a lead wire, a movable relay contact arm secured to said second plate in spaced opposed relation to the first-named arm, a movable relay contact carried by the second-named arm, an insulating sleeve mounted upon the second-named arm, the second-named arm being formed of metals having difierent thermal coeflicients of expansion and contraction, a heating element winding wound upon said insulating sleeve and having one end connected with one of said pins which is electrically connected with one of said lead wires and having its opposite end connected with a pin without a lead wire, a metallic arm connected with another of said pins which is electrically connected with one of said lead wires, a second insulating sleeve mounted upon the last-named arm, a secondheating element winding wound upon the second-named sleeve and having one end electrically connected to the pin without a lead wire with which said one end of the first winding 6 is connected and having its other end electrically connected with the last-named metallic arm.

3. A thermal relay according to claim 1, and an envelope for said relay secured to said base, and a spacer element interposed between said envelope and said platform for stabilizing the platform laterally and centering the same with respect to the axis of said base.

References Cited in the file of this patent UNITED STATES PATENTS 2,035,426 Field Mar. 24, 1936 2,109,169 Field Feb. 22, 1938 2,485,520 Warsher Oct. 18, 1948 2,527,423 Jacobsen Oct. 24, 1950 2,689,288 Wells Sept. 14, 1954 FOREIGN PATENTS 697,720 Germany Oct. 22, 1940 

